Multiple replaceable unit fuse



1951 w. T. STANLEY MULTIPLE REPLACEABLE UNIT FUSE Filed Jan. 19, 1950 5m 4 G4 I F? I 4 INVENTOR,

WILL/AM T STANLEY, 15 vflm .EETTORNEY.

Patented Dec. 25, 1951 UNITED STATES PATENT OFFICE MULTIPLE REPLACEABLE UNIT FUSE William T. Stanley, Indianapolis, Ind.

Application January 19, 1950, Serial No. 139,445

4 Claims.

This invention relates to a multiple unit fuse plug of that type wherein there are a plurality of fuse links employed, each link being brought into a circuit consecutively by revolving an external member.

A primary purpose of the invention is to provide a structure of the above indicated nature wherein the fuse links may be assembled upon a single unit so that all of the links may be replaced by the time the last of those links have been broken under abnormal circuit conditions.

A further primary object of the invention is to provide such a structure wherein the fuse link holding .element may be relatively cheaply produced and can be inserted without the necessity of having to employ a skilled electrician or having to employ any special tools. Also it is a primary object of the invention to provide a structure which will come within the normal standards of-fuse boxes and be usable in the ordinary fuse receptacle without having to require special devices and the like.

These and many other objects and advantages of the invention including the unique combination of the elements as set forth in the appended claims will become apparent to those versed in the art in the accompanying drawing, in which Fig. 1 is a view of the structure embodying the invention in top plan;

Fig. 2 is a central vertical section on the line 2-2 in Fig. 1;

Fig. 3 is a bottom plan view of the cap removed from the device;

Fig. 4 is a top plan view of the structure with the cap removed;

Fig. 5 is a central vertical section through the structure similar to that shown in Fig. 2 but wit the cap removed and the body revolved about its vertical axis;

Fig. 6 is a transverse section on the line 6-5 in Fig. 2;

Fig. 7 is a central vertical section through a modified form of the fuse element; and

Fig. 8 a bottom plan view of that modified form as shown in Fig. 7.

Referring to the drawing, in which like characters of reference indicate like parts throughout the several views, a body Ill is formed out of any suitable material such as a ceramic material to have external threads H molded therearound so as to receive thereon in a screw-threaded manner the usual type of metallic ferrule I 2. The external diameter of this ferrule I2 is made to meet the standard size to permit it to be screwthreaded into the usual fuse receiving receptacle (not shown) Axially mounted within the body I0 is a central conducting pin 13 having the external contact head l4 presented at the lower end of the body l0. Carried within the body ill to rest on the floor [5 thereof is a metallic plate l6 having a central hole I! therethrough, the margin of which is spaced from the pin l3. From this plate [6 there extends a tongue l8 through an aperture l9 molded in the body l0, and then this tongue [3 is carried up through a vertically disposed slot 20 to have its upper end turned over and down on the outside of the ferrule 12 and fixed thereto in any suitable manner such as by the solder joint 2 l.

A fuse element generally designated by the numeral 22 consists essentially of a hollow cylindrical body made out of insulating material such as fiber or plastic, this body being designated by the numeral 23. A plurality of longitudinally positioned slots 24 are provided in regular spaced apart positions circumferentially around the member 23. In the form herein shown, there are six of these slots to provide for a six fuse operation.

Along each of these slots 24 there is placed a fuse link 25, having a reduced neck portion 26. The cross-sectional area of this neck 26 is made to be such as will accommodate the desired maximum amperage of current before the neck will melt. Each link has top and bottom ends 21 and 28 respectively carried around over the respective ends of the element 23 and are thence bent downwardly and upwardly respectively within the member 23. These ends are fixed in position by forcibly pressing within the member 23 sleeves 29, herein shown as two in number, so that one sleeve 29 may be inserted from the upper end and the other sleeve 29 may be inserted from the bottom end so as to carry the fuse link ends 21 and 28 respectively along the inside of the wall of the member 23 in firm contact therewith so that the link 25 in each instance will be firmly secured within its respective slot 24. It is to be noted in this respect, that by so wrapping the ends of each link 25 around the top and bottom ends of the member 23, there is an exposed end across those ends of the element 23. The external diameter of the element 23 is made to be such that it will fit freely within the body it and have the lower ends 23 of the respective fuse links 25 rest upon the plate l6 presented at the bottom of the cavity 36 in the body [0.

The upper end of the body 10 is flared outelement 22 terminates well below the top edge 7 of this flange 3!. A pin is is provided with a shoulder 32 against which is positioned a washer 33 to be at approximately the level of the top end of the element 22, Fig. 2. From this shoulder 32, the pin extends upwardly above the level of the flange ill by a screw-threaded portion 34.

A cap 35, formed out of any suitable material, herein indicated as being made out of a plastic, has an external diameter which will permit it to be revolved within the turned flange 3|. The cap 35 revolubly receives the threaded portion 34 therethrough and is retained in position by its fit within the flange 3|. A spring 3E surrounds the threaded portion 34 and a nut 31 is screwthreadedly fixed over the outer end of that portion 54 to compress the spring 3% between that nut and the cap 35.

The cap (i5 is normally prevented from seating against the body it under pressureof this spring 36 by a crush 38 intervening between the underside of the cap and the fuse element 22 and the washer33.

Referring to Fig.3, this brush 33 is fixed to the underside of the cap 35 in any suitable manner, herein shown by means of a screw 39 passing through the brush 38 and screw-threadedly engaging the underside of the cap 35. The brush :38 is prevented from turning about the screw 39 by fitting with an upper portion in the slot 28 provided in the underside of the cap 35. The brush 33 is provided with a pair of fingers 4i and 42 which straddle the screw-threaded portion 3-4 of the pin E3. The other end 43 of this brush 38 extends sufficiently far from the pin 13 to bear'compressively on the upper end of the fuse element 22 so that it will ride over the exposed end 2? of the various fuse links .25. In other words, the two'fingers Ill and (i2 bear on the washer 33 and t e end 43 bears consecutively as the brush may be turned on those fuse :link ends 21 so that a circuit is completed from the ferrule l2 through the plate It and thence up through one of the fuse links at a time, across through the brush 38, and to the pin l3 and the exposed head is. The spring 36 thus maintained a yielding pressure of those brush ends 45, 52 and AB on the respective parts as indicated.

The body it is provided with regularly spaced apart abutments ts, one for each of the fuse links 25. In other words there are six of these abutments Ji l. In the form herein shown, the cap 35 is to be revolved in :a clockwise direction from an initial number one position consecutively to the second, third, fourth, fifth and sixth positions, each position indicating the presence ofthc brush end 43 on a fuse link end 21. The

abutments Mi are arranged to be in the path of pawls '45, herein shown as three in number and equally spaced ch'curnferentially around the underside of the cap 35. The circumferential length of the pawlsdli are made to be such that they will drop between adjacent abutments All with very little or no clearance. Considering that the cap is to travel in a clockwise direction as viewed in the drawing, the leading side of each pawl 55 has an inclined surface 46 sloping upWa-rddy from the trailing portion and merging by its upper end into a circumferential track 3.? which willnonmally bear against the top sides of the abutments M. In this respect, the fingers M and a2 and the end l3 of the brush 38 will normally be compressed against the washer 33 and the fuse link end 27, below the underside of that track 4'1 in order that the desired compressive contact between those elements be maintained.

The cap 35 is provided with a pair of finger grips 48 and 49 extending upwardly from the top side of the cap as a means for turning the cap from one position to the next. In this turning operation of the cap .35, the fuse element 22 is held against rotation by having a pin 50 extend radially therefrom and enter a slot 5| provided in the body l0.

In operation, the cap 35 when delivered to the purchaser or used has its number one position set adjacent the indicator 52, Fig. 1. The assembly is then ready to be screwed into the fuse receptacle in the usual manner. Should an overloadoccur in the circuit, the link 25 having its end 2? in contact with the brush end 43 will have the neck .26 melt and thus break the circuit. When the condition causing that overload has been removed, the finger grips t8 and its will be grasped and the cap 35 revolved to the number two position to bring the next succeeding fuse link end 21 relatively under the brush ended. In other words the brush end 43 is caused to travel ciroumferentially. around the fuse element 22 until it comes to that next presented fuse end .23. After all of the fuse links .25 have been so used, that is they have been severed through their links or necks 26, no circuit can then be established through the assembly.

lhe nut 3? is then unscrewed in order to perrnit the cap 35 to be withdrawn, from over the body Ill, and the used fuse element 22 .is withdrawn from the body as and a new one is replaced, having the pin .55 entered in the sloth! as above indicated, whereupon the cap .35 may be returned to its position for usage and the nut 3'! tightened downon the end of the screw-threaded portion 3d of the pin l3.

Referring to Figs. 7 and 8, Whereinthere is a modified form of the fuse element shown and generally designated by the numeral 53, the same cylindrical body 23 is employed, but the fuselinks 5d instead of being separate elements are attached 'by their lower ends to an annulus 5%, ,Fig'. 8. In this modification, the annulus 55 is in ,contact with the bottom plate iii. A single internal sleeve 55 is employed 'to be inserted from the upper end of the body 23 in order to hold the ends 5'1 of the individual links 5d firmly in posi tion so that these upper ends 5'1 will then be positioned to be contacted consecutively one after the other by the brush end 13 as above indicated in reference to the element 22.

The abutments 2 5 are provided with straight end faces in order to prevent counterclockwiseturning of the cap 35. The inclined faces 46 ahead of the pawls d5 permit the cap to lift itself against the yielding pressure of the spring 3G to carry the pawls over the outer ends of the abutments 4 and then drop the pawls 45 in between the next space between the succeeding abutment (it.

While I have herein shown and described my invention in the one particular forn1,.it;is obvious that structural changes may be employed without depar ing from the spirit of the invention, and I therefore do not desire to be limited to that precise form beyond the limitations whichmay be imposed by the following claims.

I claim:

.1. In a replaceable, multiple fuse plug having a body of insulating material formed with a central cylindrical well, the body being surrounded by a metallic screw-threaded ferrule, a central pin headed on the outer end and extending axially through said well, an annular metal plate on the floor of said well interconnected with said ferrule, and a cap revolubly carried on said pin over said well with a brush interconnecting with said pin: a fuse unit removably carried in said well comprising a cylindrical sleeve of insulating material; a plurality of fuse links spaced apart circumferentially around said sleeve, the ends of the links being carried around the ends of said sleeve to have at least one set of ends extend along the inner side of the sleeve; and a second sleeve of insulating material telescoped within said first sleeve compressibly engaging said one set of fuse link ends between it and the first sleeve; said two sleeves and interengaged fuse links having an external diameter to enter freely said well to rest on said plate by one set of fuse link ends to present the other set of fuse link ends in the path of said brush.

2. A multiple link fuse element comprising a cylindrical sleeve of insulating material; a p1u rality of fuse links extending longitudinally of and in circumferentially spaced apart positions around the outer face of said sleeve, the ends of said links in each instance being folded over the ends of the sleeve and into the bore thereof; a second sleeve of insulating material entered into one end of said first sleeve compressibly engaging and retaining the ends of the links overturning that first sleeve end between the two sleeves.

3. A multiple link fuse element comprising a a cylindrical sleeve of insulating material; a plurality of fuse links extending longitudinallyof and in circumferentially spaced apart positions around the outer face of said sleeve, the ends of said links in each instance being folded over the ends of the sleeve and into the bore thereof; a second sleeve of insulating material entered into one end of said first sleeve ccinpressibly engaging and retaining the ends of the links overturning that first sleeve end between the two sleeves; and a third sleeve of insulating material compressibly inserted in the other end of said first sleeve to engage and retain therebetween 6 the fuse link ends overturning that other end of the first sleeve; the outer ends of both said second and third sleeves being inside of the planes formed by the outer overturned ends of said fuse links.

4. In a replaceable, multiple fuse plug having a body of insulating material formed with a central cylindrical well, the body being surrounded by a metallic screw-threaded ferrule, a central pin headed on the outer end and extending axially through said well, an annular metal plate on the floor of said well interconnected with said ferrule, and a cap revolubly carried on said pin over said well with a brush interconnecting with said pin: a fuse unit removably carried in said well comprising a cylindrical sleeve by insulating material; a plurality of fuse links spaced apart circumferentially around said sleeve, the ends of the links being carried around the ends of said sleeve to have at least one set of ends extend along the inner side of the sleeve; and a second sleeve of insulating material telescoped within said first sleeve compressibly engaging said one set of fuse link ends between it and the first sleeve; said two sleeves and interengaged fuse links having an external diameter to enter freely said Well to rest on said plate by one set of fuse link ends and to present the other set of fuse link ends in the path of said brush; and abutment means interengaging between said unit and said body by entrance of the unit into said well to hold said unit against rotation in said Well.

WILLIAlVI T. STANLEY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,475,200 Terrell et al Nov. 27, 1923 1,577,447 Bruckner Mar. 23, 1926 1,914,871 Siampos June 20, 1933 2,492,301 Linton Dec. 27, 1949 FOREIGN PATENTS Number Country Date 552,955 France Feb. 1, 1923 

